BRCA1 and breast cancer: To investigate the relationship between BRCA1 and FOXO3 expression, western blot analysis was performed on a panel of five breast cancer cell lines, which include the luminal-type MCF-7 cells with wild-type-competent BRCA1 and the basal-type lines HCC70, MDA-MB-231, MDA-MB-436 and MDA-MB-468 expressing either low or mutated BRCA1.